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A Cartazzi axle is a design of leading or trailing wheel support[1][2][3] used worldwide.[4][5][6][7][8] The design was used extensively on the former LNER's Pacific steam locomotives and named after its inventor F.I. Cartazzi,[9] formerly of the Great Northern Railway. It should not be confused with a pony truck as it does not pivot at all.[8] The axle does, however, have sideways play built in to accommodate tight curves. Cartazzi's design causes the weight of the locomotive to exert a self-centring action on the trailing wheels.[10]

The Cartazzi design was also sometimes applied to driving wheel axles on longer wheelbase locomotives.[11]


On small scale models the trailing wheels of Cartazzi-axled locomotives are often flangeless to allow negotiation of tighter, non-prototypical curves, or the Cartazzi axle has been replaced with a pony truck for the same reason.


  1. ^ "Three-Cylinder Balanced Compound "Atlantic" Engines; Great Central Railway". The Railway Engineer. XXVII (312): 6. January 1906 – via Google Books.
  2. ^ Ellis, Cuthbert Hamilton (1949). Some Classic Locomotives. Allen & Unwin. p. 156 – via Google Books. The leading and trailing carrying axles had sideplay through Cartazzi sliding axleboxes
  3. ^ Nock, Oswald Stevens (1967). Steam Railways of Britain in Colour. Blandford P. p. 144. The leading pair of wheels had the Cartazzi form of axle box...
  4. ^ "Six-Coupled Tank Locomotive, Imperial Rys. of Japan". The Locomotive Magazine & Railway Carriage & Wagon Review. XV (198): 39. February 15, 1909 – via Google Books.
  5. ^ Coleman, F.C. (February 9, 1918). "Garratt Type Locomotive for the Sao Paulo Ry., Brazil". Railway Review. 62 (6): 187–188 – via Google Books.
  6. ^ "Four-Wheel Coupled Locomotive for the Dutch States Railways". Engineering: 143. February 1, 1901 – via Google Books.
  7. ^ "Powerful Articulated Narrow Gage Locomotives for Tasmania". Scientific American Supplement. New York. LXXVI (1968): 180. September 20, 1915 – via Google Books.
  8. ^ a b "Roundhouse Nightmare". Trains. Kalmbach Publishing Company. 17: 18. 1956 – via Google Books.
  9. ^ Headrick, Daniel R. (1988). The Tentacles of Progress: Technology Transfer in the Age of Imperialism, 1850-1940. Oxford University Press. p. 84. ISBN 0-19-505115-7 – via Google Books.
  10. ^ Ransome-Wallis, P., ed. (2001) [1959]. Illustrated Encyclopedia of World Railway Locomotives. Mineola, New York: Dover Publications. p. 250. ISBN 0-486-41247-4 – via Google Books.
  11. ^ "Modern British Practice in Tank Locomotives - II". The Mechanical World. Machester, England. XLIV (1139): 212. October 30, 1908 – via Google Books. ... the coupled wheelbase, which is 16ft. 6in., is not rigid, the leading axle boxes having 1¼in. side play. This is compensated for in the leading length of the coupling rods and controlled by sliding caps on the axle boxes on the Cartazzi principle.